This invention relates to apparatus in the form of a medico-surgical tube having a main tubular shaft with a main lumen and a small-bore minor lumen extending along the wall of the main shaft, the minor lumen being provided at least in part by a small-diameter tube attached along a part of its length with the main shaft.
Laryngeal mask airways are used to ventilate and to supply anesthetic gas to a patient during surgery. Laryngeal mask airways differ from endotracheal tubes, which extend into the trachea and terminate beyond the vocal folds. By contrast, laryngeal mask airways have a tubular shaft opening into the centre of a generally elliptical mask or cuff, which is inflated to seal in the region of the hypopharnyx, at the top of the trachea. The cuff is inflated with air supplied along a small-bore inflation line communicating with the interior of the cuff. The inflation line is not usually attached with the tubular shaft, which can be an inconvenience because it complicates packing and use of the airway. Laryngeal masks are described in, for example: U.S. Pat. No. 5,355,879, U.S. Pat. No. 5,305,743, U.S. Pat. No. 5,297,547, U.S. Pat. No. 5,282,464, GB 2267034, U.S. Pat. No. 5,249,571, U.S. Pat. No. 5,241,956, U.S. Pat. No. 5,303,697, GB 2317830, GB 2249959, GB 2111394, EP 448878, U.S. Pat. No. 4,995,388, GB 2205499, GB 2128561, GB 2298797, GB 2321854, GB 2334215, GB 2323289, GB 2323290, GB 2318735 and GB 2330312.
A problem generally with cuffed medico-surgical tubes, such as laryngeal masks and tracheal tubes is that the users often wish to cut the machine end of the shaft of the tube to length in order not to have an excessive length of tube protruding from the mouth or nose. In tubes having an inflation line attached to the main shaft, the presence of the inflation line limits the extent to which the tube can be cut to length.
It is an object of the present invention to provide alternative medico-surgical apparatus.
According to one aspect of the present invention there is provided apparatus of the above-specified kind, characterised in that the small-diameter tube is attached with the shaft in a manner such that it can be detached from the shaft to reduce the length attached with the shaft.
The shaft may have a channel extending along its external surface, the small-diameter tube being attached with the shaft in the channel. Alternatively, the small-diameter tube may be attached with the shaft by a rupturable bond.
According to another aspect of the present invention there is provided apparatus in the form of a laryngeal mask airway including a tubular shaft with a channel extending along its external surface and a mask portion mounted at the patient end of the shaft, the mask portion having a mount member mounted on the shaft and an inflatable cuff mounted on the mount member such that the cuff can be inflated to seal with surrounding tissue, characterised in that the mount member has a channel extending between the cuff and the channel on the shaft and a small-diameter inflation line tube extending within the channel along the shaft and within the channel in the mount member to communicate with the interior of the cuff.
The channel on the shaft is preferably shaped to retain mechanically the small-diameter tube. Preferably, the channel on the shaft in section is the major part of a circle and it may have a notch or a plurality of notches spaced from one another along the channel to provide a plurality of locations where the small-diameter tube can extend out of the channel. The shaft may be helically reinforced.
According to a further aspect of the present invention there is provide a method of preparing medico-surgical apparatus, the apparatus including a main tubular shaft with a main lumen, an inflatable cuff towards the patient end of the shaft and a small-bore minor lumen extending along the shaft and opening into the cuff, the minor lumen being provided at least in part by a small-diameter tube detachably attached along a part of its length to the shaft, the method including the steps of peeling the small-diameter tube away from the shaft to a desired location and then cutting the machine end of the shaft on the machine side of the desired location to give the shaft a desired length.